Civil Services Prep

Prelims 2012 · Science and Technology · Question 13

What is the role of ultraviolet (UV) radiation in the water purification systems?

  1. It inactivates/kills the harmful microorganisms in water.
  2. It removes all the undesirable odours from the water.
  3. It quickens the sedimentation of solid particles, removes turbidity and improves the clarity of water.

Which of the statements given above is/are correct?

  1. 1 only
  2. 2 and 3 only
  3. 1 and 3 only
  4. 1, 2 and 3

Answer

1 only

1. Correct. UV radiation is used for disinfection; it damages the DNA/RNA of bacteria, viruses and other pathogens, thereby inactivating them.

2. Incorrect. UV treatment does not remove odours; odour removal usually needs activated carbon, aeration, oxidation, etc.

3. Incorrect. UV does not aid sedimentation or remove turbidity; suspended particles are handled by coagulation, sedimentation and filtration. In fact, high turbidity can reduce UV effectiveness.

Therefore, only statement 1 is correct.

  1. Which of the following statements with regard to genetic medicine is/are correct ? 1. Genetic medicines…
  2. Which of the following statements with regard to Large Language Models (LLMs) used in machine learning is/are…
  3. Which of the following statements with regard to stealth technology is/are correct ? 1. Stealth objects have a…
  4. Which of the following statements with regard to Black Boxes used in modern aircrafts is/are correct ? 1. They…
  5. Consider the following statements with regard to involvement of private entities in India's space programme :…
  6. Which of the following statements with regard to drone swarms is/are correct ? 1. They use Terahertz band of…